If at first you do not succeed, try, try again. Some will dismiss President Barack Obama’s laundry list of steps on global warming as flimsy. Having failed to persuade Congress to pass a cap-and-trade system in his first term, he is retreating to the more modest realm of executive action in his second.

如果第一次没有成功，那就尝试、再尝试。美国总统巴拉克•奥巴马(Barack Obama)列出了一长串旨在解决全球变暖问题的措施，但有人不屑一顾，认为这些措施毫无说服力。在第一届任期内，奥巴马未能说服国会批准碳排放“限量及交易”(cap and trade)机制；到了第二任期，他更加谨慎，采取行政措施。

Yet it is hard to see what else he can do. There is scant chance of persuading the 113th Congress to acknowledge man-made climate change, still less to approve tough action to slow it. Modest though they are, Mr Obama’s steps will have positive outcomes. Opponents say he is launching a “war on coal”. Mr Obama should embrace that as a virtue.

然而，很难说他还能做些什么。要说服第113届国会承认气候变化是人为因素引起的，机会十分渺茫，更遑论让国会批准强硬措施来减慢气候变化的速度了。奥巴马的措施虽然谨慎，但将产生积极结果。反对者表示，奥巴马正在发起一场“反煤碳之战”。奥巴马应该把这话当作赞扬来欣然接受。

Two benefits will come from his order for Environmental Protection Agency regulations to reduce power plant emissions. The biggest will be its impact abroad. At a time of drift in global climate talks, it is good for Washington to be seen to be taking action. Though the US is still the second-largest emitter in the world, its trajectory has been downwards for several years. Partly because of the Great Recession, and partly because of the boom in natural gas, the US is on course to reduce its carbon output to 17 per cent below its 2005 levels by 2020. Yet global emissions keep rising. The most valuable thing the US can do is rekindle a sense of international urgency. The timing is also good when China, and others, are having their own doubts about coal.

奥巴马命令美国国家环境保护局(EPA)制定条例，以减少电厂排放，这会带来两点好处。最大的好处是对国外的影响。在全球气候谈判前途未卜之际，美国政府采取行动会令外界感到欣慰。尽管美国依然是全球第二大温室气体排放国，但近几年来其排放轨迹逐渐下滑。部分由于经济萧条的影响，部分由于天然气的繁荣，到2020年美国的碳排放比重将降低到17%，低于2005的水平。然而全球排放量有增无减。美国能做的最有价值的事情是重新唤醒国际社会的紧迫感。在中国以及其他国家本身也开始质疑煤炭之际，时机把握得相当合适。

Second, the US power sector needs to be cleaned up. In an ideal world, Congress would pass a carbon tax and allow the market to decide the rest. In the real world, regulatory targeting make sense. It follows the modest success of earlier mandates to improve fuel efficient standards for cars and household appliances. Power plants generate a third of overall US emissions, and coal is responsible for most of that. Given the growing impact of US hydraulic fracturing, the timing is good for Washington to convert the switch to gas into a “dash for gas”. Coal’s days ought to be numbered.

其次，需要对美国电力行业进行整治。理想情形是，美国国会将批准征收碳排放税，并让市场去决定其他事情。在现实世界中，设定监管目标是明智的。此前旨在提高汽车和家用电器燃油效率的命令，收效差强人意，因此随后才设定了监管目标。发电厂碳排放量占全美碳排放总量的三分之一，其中源于煤炭的排放占绝大部分。鉴于水力压裂技术在美国的应用日益广泛，美国政府选择把转向天然气的策略升级为“向天然气冲刺”，时机恰到好处。告别煤炭的日子应该屈指可数了。

Mr Obama’s actions will have costs, too. Having already objected to Gina McCarthy, the president’s choice to head the EPA, Senate Republicans may now kill her nomination. There will also be a flood of lawsuits challenging the EPA’s new rule book, which will in any case take a year or two to draw up. These are prices worth paying. The alternative would be for Mr Obama to throw up his hands in despair. Something must surely be better than nothing.

奥巴马的行动也有代价。奥巴马提名吉娜•麦卡锡(Gina McCarthy)掌管EPA，但已遭到参议院共和党议员的反对，如今这项提名可能会被否决。此外，无论如何需要一两年才能出台的EPA新规则手册，也将引发一波诉讼潮。这些代价值得付出。否则，奥巴马就只能在绝望中束手无策了。有所作为总比无所作为好一些。